Normal is 7 On 7 Off. Reserve pays more because you do not have a set schedule, your trips are movable and you are available to work more days. Depending on fleet and seat this schedule can go senior or occaisionally be junior assigned. The following is from the contract Blue Book:
19.3 Reserve Schedule
Maximum duty days: 18 in a calendar month required by the Company, except when otherwise allowed (e.g., training events).
Maximum tour length: 7 consecutive days required by the Company in any single duty tour, except when otherwise allowed (e.g. training events).
Reserve schedule is subject to change at any time (with the exception of the 4 “H” days per month).
19.3(b) Hard Days Off “H” Days
Pilots are entitled to bid for two 2-day periods per month as “H” days OR may elect to request all of them be placed in a single 4-day block.